class_docstr: Extends the observer LogReturns to show two instruments
code: def __init__(self):
      super(LogReturns2, self).__init__()
  
      self.logret2 = self._owner._addanalyzer_slave(
          bt.analyzers.LogReturnsRolling,
          data=self.data1,
          **self.p._getkwargs(),
      )
  
file_path: backtrader/backtrader/observers/logreturns.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import backtrader
label_desc: Use image node_id 1 to create a new LogReturns2 object from inherited base classes: LogReturns with example: obj = LogReturns2()